The Prevalence and Determinants of Undiagnosed and Diagnosed Type 2 Diabetes in Middle-Aged Irish Adults

1 Dec 2014

There is an ongoing need for contemporary data on the prevalence of T2DM within Ireland. This could help formulate strategies that further develop effective diabetes prevention, detection and management.

Aims

The aim of this study was to assess the prevalence of undiagnosed and diagnosed T2DM in middle-aged Irish adults and compare features in order to investigate why certain individuals remain undetected. In particular, we determined the extent to which the probability of diagnosis is influenced by access to primary care as defined by health insurance status.

Design

The Cork and Kerry Diabetes and Heart Disease Study (Phase II) was a single centre, cross-sectional study conducted between 2010 and 2011, based on a population representative random sample of 2,047 men and women aged between 50-69 years (49.2% male).

Methods

All study participants attended the clinic in the morning after an overnight fast and blood samples were taken on arrival. Lipid and lipoprotein measurements were classified according to International Diabetes Federation guidelines.

Weight and height were measured to the nearest 0.1 kg and 0.1 cm respectively. Body mass index (BMI) was calculated as weight divided by the square of height.

Stepwise forwards and backwards entry elimination logistic regressions were performed to explore socioeconomic, metabolic and other health-related variable associations with undiagnosed and diagnosed T2DM. Model stability was determined using the likelihood ratio. The discriminatory properties of clinically relevant predictor variables identified in regression analyses were assessed using the receiver operating characteristic curve.

Results

The total prevalence of T2DM was 8.5% (95% CI: 7.4%-8.8%). The prevalence of undiagnosed diabetes was 3.5% (95% CI: 2.8%-4.4%), representing 41% of all T2DM cases. A significantly greater proportion of male subjects (11.1%) had T2DM compared to females (6.0%, P <0.001).